"My favourite three words in the world," begins Guy Garvey. "Good evening Glastonbury!" Thus begins perhaps the most relentless charm offensive that Worthy Farm has ever seen. Perhaps there are people out there with a personal animus towards Garvey but it's hard to imagine anyone else resisting his immense down-to-earth charisma. Noting their combination of anthemic outreach and self-effacing northern humour, a colleague approvingly called them "the Phoenix Nights U2".

Timing plays a big part. People have generally settled in by Saturday anyway; this year they've just enjoyed an afternoon of sunshine and clear skies. To this ballooning optimism Elbow bring graceful celebrations of love and friendship and an emotional directness that floors you. The crowd radiate goodwill; Elbow respond with gratitude and generosity.

No other frontman could get away with as much borderline corny showboating as Garvey. "Let's do some festival things," he suggests guilelessly, before leading what he calls "a reverse Mexican wave", in which row after row duck down in a rippling human sea. "I'm sick with power," he quips afterwards. He also downs a pint, gets everyone to whistle the melody of Lippy Kids and enlists them to mark the band's 20th anniversary by singing Happy Birthday before Weather to Fly. "Are we having the time of our lives?" he sings, and like many Elbow lyrics it seems tailor-made for the occasion. England would have to win the World Cup before you saw this many men wiping away tears again. People talk about bands having "a Glastonbury moment". Elbow have at least six.

The euphoric Open Arms is one, and finally there's a breathtaking One Day Like This. Garvey lets the crowd sing the final chorus unaccompanied: a fitting conclusion for a band whose populist warmth is currently unrivalled. Their Other Stage set in 2008 helped catapult The Seldom Seen Kid to ubiquity. This performance is not just the highlight of this year's festival so far but one of the all-time greats.